Efficient cleaning and etching of high aspect ratio structures

ABSTRACT

A method for treating a substrate includes arranging a substrate in a processing chamber. At least one of a vaporized solvent and a gas mixture including the solvent is supplied to the processing chamber to form a conformal liquid layer of the solvent on exposed surfaces of the substrate. The at least one of the vaporized solvent and the gas mixture is removed from the processing chamber. A reactive gas including a halogen species is supplied to the processing chamber. The conformal liquid layer adsorbs the reactive gas to form a reactive liquid layer that etches the exposed surfaces of the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/684,415, filed on Jun. 13, 2018. The entire disclosure of theapplication referenced above is incorporated herein by reference.

FIELD

The present disclosure relates to methods for processing substrates andmore particularly to methods for efficiently cleaning and etchingsubstrates including high aspect ratio (HAR) structures.

BACKGROUND

The background description provided here is for the purpose of generallypresenting the context of the disclosure. Work of the presently namedinventors, to the extent it is described in this background section, aswell as aspects of the description that may not otherwise qualify asprior art at the time of filing, are neither expressly nor impliedlyadmitted as prior art against the present disclosure.

Fabrication of substrates such as semiconductor wafers typicallyrequires multiple processing steps that may include material deposition,planarization, feature patterning, feature etching, and/or featurecleaning. These processing steps are typically repeated one or moretimes during processing of the substrate. As semiconductor devicescontinue to scale down to smaller feature sizes, high aspect ratio (HAR)structures such as vias and trenches are increasingly required toachieve desired device performance objectives. The HAR structures posechallenges to wet clean and wet etch efficiency due to reduced diffusionand surface charge layer overlap in geometrically confined spaces.

SUMMARY

A method for treating a substrate includes a) arranging a substrate in aprocessing chamber; b) supplying at least one of a vaporized solvent anda gas mixture to the processing chamber to form a conformal liquid layerof the solvent on exposed surfaces of the substrate; c) removing the atleast one of the vaporized solvent and the gas mixture from theprocessing chamber; and d) supplying a reactive gas including a halogenspecies to the processing chamber. The conformal liquid layer adsorbsthe reactive gas to form a reactive liquid layer that etches the exposedsurfaces of the substrate.

In other features, the reactive liquid layer reacts with the exposedsurfaces of the substrate to create a gas product. The exposed surfacesof the substrate are etched without forming residue. The at least one ofthe vaporized solvent and the gas mixture is selected from a groupconsisting of a polar solvent, water, peroxide, isopropyl alcohol,acetone, carbon tetrachloride, hexane, methanol, and ethanol.

In other features, the reactive gas is selected from a group consistingof hydrogen fluoride gas, hydrogen chloride gas and hydrogen bromidegas. The substrate includes a plurality of high aspect ratio (HAR)features having a depth to width that is greater than or equal to 5:1.

In other features, prior to supplying the at least one of the vaporizedsolvent and the gas mixture to the processing chamber, setting apressure in the processing chamber to a pressure range from 1 Torr to 10Torr. Prior to supplying the at least one of the vaporized solvent andthe gas mixture to the processing chamber, setting processingtemperature in the processing chamber to a temperature range from 0C° to400° C. Prior to supplying the at least one of the vaporized solvent andthe gas mixture to the processing chamber, setting processingtemperature in the processing chamber to a temperature range from 150 C°to 400° C.

In other features, the reactive liquid layer etches the exposed surfaceat an etch rate in a range from 10 Angstroms/min to 100 Angstroms/min.In other features, the method includes performing a plurality of cyclesincluding a) to d).

In other features, the reactive liquid layer etches the exposed surface0.2 Angstroms to 1 Angstrom during each cycle of the plurality ofcycles. In other features, the method includes, prior to b), supplyingan oxidizing gas to the processing chamber for a predetermined periodand evacuating the oxidizing gas.

In other features, the oxidizing gas includes a gas selected from agroup consisting of molecular oxygen, ozone, hydrogen peroxide, nitrousoxide and nitrogen dioxide. The oxidizing gases are supplied with remoteplasma. The oxidizing gases are supplied at a processing temperature ina range from 100° C. to 400° C.

In other features, the method includes performing wet cleaning of thesubstrate after d). The reactive liquid layer reacts with the exposedsurfaces of the substrate to create a gas product. The exposed surfacesof the substrate are etched without forming residue. In other features,a) to d) are performed in an inductively coupled plasma (ICP) chamber.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description, the claims and the drawings. Thedetailed description and specific examples are intended for purposes ofillustration only and are not intended to limit the scope of thedisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a side cross-sectional view of an example of a substrateincluding high aspect ratio (HAR) structures;

FIGS. 2A and 2B are side cross-sectional views of an example of thesubstrate during cleaning or etching of the substrate according to thepresent disclosure;

FIG. 3 is a flowchart of an example of a method for cleaning or etchingof the substrate according to the present disclosure;

FIGS. 4A to 4C are side cross-sectional views of the substrate duringcleaning or etching of the substrate according to the presentdisclosure;

FIG. 5 is a flowchart of an example of a method for cleaning or etchingof the substrate according to the present disclosure;

FIGS. 6A and 6B are functional block diagrams of a processing chamberaccording to the present disclosure; and

FIG. 7 is a functional block diagram of a substrate processing toolincluding at least one processing chamber for cleaning and etchingaccording to the present disclosure.

In the drawings, reference numbers may be reused to identify similarand/or identical elements.

DETAILED DESCRIPTION

As feature sizes shrink in advanced process nodes, high aspect ratio(HAR) structures are becoming more common. As used herein, HARstructures refer to features having aspect ratios greater than 5:1, 10:1or 20:1. The HAR structures pose challenges to wet clean and wet etchefficiency due to reduced diffusion and surface charge layer overlap ingeometrically confined spaces. A method according to the presentdisclosure overcomes this challenge using gas or vapor phasepre-treatment to generate an adsorbed liquid layer that conformallycoats the HAR structures and improves subsequent cleaning and removalefficiency.

Materials diffuse much faster (on the order of x10⁴ faster) in the gasor vapor phase as compared to the liquid phase. The methods describedherein form a liquid layer of adsorbed reactive species on the HARstructures from the gas phase or the vapor phase. Due to the adsorbedliquid layer, chemical reactions are able to modify the underlyingresidue or films on the surface of the substrate and improve cleaningefficiency for the residue or etch efficiency of the film.

In some examples, the process is performed in a vacuum chamber at vacuumwith controlled vapor exposure at a pre-determined temperature. In someexamples, the pressure is in a range from 1 T to 10 T. In some examples,the substrate temperature is maintained in a range from 0° C. to 400° C.during etching or cleaning. In some examples, the substrate temperatureis maintained in a range from 150° C. to 400° C. during etching orcleaning. In other examples, the process is performed at atmosphericpressure in a processing chamber. Whether or not a vacuum chamber isused may be determined by the volatility of the solvent at differentprocess temperatures and/or pressures that are used during the cleaningor etching steps. If the solvent is not volatile at atmosphericpressure, a vacuum chamber can be used.

The method according to the present disclosure is similar to atomiclayer etching (ALE) in that reactants are introduced in the gas or vaporphase. However, in ALE, the adsorbed layer is mostly a monolayer andetching stops at a monolayer reaction. As a result, the etch rate isslow, e.g. on the order of 0.2 A to 1 A of material per cycle. Inaddition, ALE processes do not address cleaning efficiency. The methodaccording to the present disclosure provides a higher etch rate. In someexamples, the etch rate is on the order of ˜10 A/min to 100 A/min.Another advantage of the method according to the present disclosure isthe inherently high selectivity as compared to wet clean chemistry. Thecondensed liquid layer acts effectively like a liquid in wet cleanchemistry.

Referring now to FIG. 1, a substrate 100 includes a first layer 110 anda second layer 114 deposited on the first layer 110. The substrate 100includes a plurality of high aspect ratio (HAR) structures 108 that aredefined in the first layer 110 and the second layer 114. For example,particles or residue 120 may be located at a bottom portion of the HARstructures 108 after a prior processing step and may need to be removed.The particles or residue 120 may be difficult to remove during cleaningdue to the depth of the HAR structures.

Referring now to FIGS. 2A and 2B, during cleaning and/or etchingprocesses, the substrate 100 is exposed to a gas mixture or a vaporizedsolvent A(g), where A is the solvent. For example, the substrate 100 maybe controlled to a differential temperature relative to other componentsin the processing chamber (e.g. the substrate 100 is maintained at alower temperature). The solvent 100 can be introduced into theprocessing chamber as a gas mixture that condenses as a liquid on thesubstrate 100. Alternately, gas vapor can be supplied to the processingchamber.

In FIG. 2A, the gas or vapor condenses on the second layer 114 and formsa conformal liquid layer 210 (which is adsorbed on an exposed surface ofthe second layer 114 as shown). In some examples, the solvent isselected from a group consisting of a polar solvent, water (H₂O),peroxide (H₂O₂), isopropyl alcohol (C₃H₈O or IPA), acetone ((CH₃)₂CO),carbon tetrachloride (CCl₄), hexane (C₆H₁₄), methanol (CH₃OH or MeOH),ethanol (C₂H₆O or EtOH) and/or other suitable solvent. In some examples,the solvent that is used is selected based on the film material of thesecond layer 114 that is to be cleaned or etched.

Subsequently, the substrate 100 is exposed to a reactive gas B(g), whereB includes a halogen species such as fluorine (F), chlorine (Cl) orbromine (Br) as shown in FIG. 2B. In some examples, the reactive gasincludes hydrogen fluoride gas (HF), hydrogen chloride gas (HCl) orhydrogen bromide (HBr) gas. The reactive species is adsorbed by theliquid layer 210 to create a reactive liquid layer 220 including thereactive species. The reactive liquid layer 220 cleans or etches thesecond layer 114 during an etch period or clean period. The reaction byproduct formed is in the gas phase and leaves the HAR without formingany residue, as indicated by gas C(g).

In some examples, such as during cleaning, a wet clean step may beperformed after exposure to the reactive species in the reactive liquidlayer 220. In some examples, the wet clean step uses mild chemistry. Insome examples, the wet clean step includes rinsing the substrate withdeionized water (DIW) or ozone dissolved deionized water (DIO₃).

Referring now to FIG. 3, a method 300 for cleaning or etching of thesubstrate is shown. At 310, the substrate is arranged in a processingchamber. At 314, substrate temperature and/or chamber pressure arecontrolled. At 318, a gas mixture and/or vaporized solvent are suppliedto the processing chamber for a first predetermined period. The gasmixture and/or vaporized solvent are adsorbed onto the exposed surfaceof the second layer 114 as a liquid layer. At 322, a reactive gas issupplied to the processing chamber for a second predetermined period. Insome examples, the reactive gas includes a halogen species. Thesubstrate is exposed to the liquid layer including the reactive speciesfor a third predetermined period sufficient for cleaning and/or etching.At 326, a wet clean step may optionally be performed after the cleaningor etching step. The process can be repeated one or more times.

Referring now to FIGS. 4A to 4C, the substrate 100 of FIG. 1 may becleaned or etched using another process. The substrate 100 is exposed toan oxidizing gas mixture in FIG. 4A, which oxidizes an exposed surfaceof the second layer 114 as shown at 410. In FIG. 4B, the substrate 100is optionally exposed to a gas mixture or a vaporized solvent A(g) priorto exposure to reactive gas B(g). The gas mixture or vaporized solventcondenses on the second layer 114 to create a conformal liquid layer420. In some examples, the solvent is selected from a group consistingof a polar solvent, water (H₂O), peroxide (H₂O₂), isopropyl alcohol(C₃HBO or IPA), acetone ((CH₃)₂CO), carbon tetrachloride (CCl₄), hexane(C₆H₁₄), methanol (CH₃OH or MeOH) and/or ethanol (C₂H₆₀ or EtOH).

Subsequently, the substrate 100 is exposed to a reactive gas B(g), whereB includes a halogen species such as fluorine (F), chlorine (Cl) orbromine (Br) as shown in FIG. 4C. The reactive species is adsorbed bythe liquid layer 420 to create a liquid layer 430 including the reactivespecies. The liquid layer 430 cleans or etches the second layer 114during a cleaning period or etch period, respectively. The reaction byproduct formed is in the gas phase and leaves the HAR without formingany residue, as indicated by gas C(g).

In some examples, such as during cleaning, a simple wet clean step maybe performed after exposure to the reactive species (in the liquid layer430) using mild chemistry (as compared to other clean steps such assulfuric peroxide mixtures (SPM)). In some examples, the simple wetclean may include rinsing the substrate with deionized water (DIW) orozone dissolved deionized water (DIO₃).

Referring now to FIG. 5, a method 500 for cleaning or etching of thesubstrate is shown. At 510, the substrate is arranged in a processingchamber. At 514, substrate temperature and/or chamber pressure arecontrolled. At 518, an oxidizing gas is supplied to the processingchamber during a first predetermined period. In some examples, theoxidizing gas includes molecular oxygen (O₂), ozone (O₃), peroxide(H₂O₂), nitrous oxide (N₂O), nitrogen dioxide (NO₂), although otheroxidizing gases can be used. The oxidizing gases can be supplied withremote plasma using a remote plasma source (RPS) or using thermalreactions at elevated processing chamber temperatures. In some examples,the elevated processing chamber temperatures are in a range from 100° C.to 400° C. In some examples, the elevated temperatures for 02, 03 andH₂O₂ are in a range from 50° C. to 250° C. In some examples, theelevated temperatures for N₂O and NO₂ are in a range from 200° C. to400° C.

At optional step 522, gas and/or vaporized solvent are supplied to theprocessing chamber for a second predetermined period. The gas and/orvaporized solvent are adsorbed onto the exposed surface of the secondlayer 114 as a liquid layer. At 526, a reactive gas is supplied to theprocessing chamber for a third predetermined period. The reactive gasincludes a halogen species. The substrate is exposed to the liquid layerincluding the reactive species for a fourth predetermined periodsufficient for cleaning and/or etching. At 530, a wet clean step mayoptionally be performed. The process can be repeated one or more timesas needed.

In one example, the method of FIG. 5 is used to selectively etchTiN/TiSiN film. In this example, the oxidation gas is supplied usingthermal oxidation (O₃ or O₂/N₂) or remote inductively coupled plasma(ICP) (O₂ or O₂/N₂). The oxidation step creates a TiO₂ layer. Thesolvent includes an alcohol such as IPA, MeOH or EtOH. The reactive gasincludes HCl, HF or HBr. The TiO₂ is converted into TiClx, TiF_(y), orTiBr_(z) (where x, y and z are integers), which is volatile.

Advantages of the method described in FIG. 5 include higher cleaningefficiency. Gas diffusion is on the order of ˜10⁴ higher than liquiddiffusion and there are no Debye length constraints. The process islimited by oxidation thickness, which provides uniformity control.Additional thickness can be removed by cycling the process one or moretimes.

Referring now to FIG. 6A, an example of a substrate processing chamber600 for performing etching or cleaning at vacuum is shown. While aspecific substrate processing chamber is shown and described, themethods may be implemented using other types of substrate processingsystems. For example, a substrate processing system operating atatmospheric pressure can be used. The substrate processing chamber 600includes a lower chamber region 602 and an upper chamber region 604. Thelower chamber region 602 is defined by chamber sidewall surfaces 608, achamber bottom surface 610 and a lower surface of a gas distributiondevice 614.

The upper chamber region 604 is defined by an upper surface of the gasdistribution device 614 and an inner surface of a dome 618. In someexamples, the dome 618 rests on a first annular support 621. In someexamples, the first annular support 621 includes one or more spacedholes 623 for delivering process gas to the upper chamber region 604. Insome examples, the process gas is delivered by the one or more spacedholes 623 in an upward direction at an acute angle relative to a planeincluding the gas distribution device 614, although otherangles/directions may be used. In some examples, a gas flow channel 634in the first annular support 621 supplies gas to the one or more spacedholes 623.

The first annular support 621 may rest on a second annular support 625that defines one or more spaced holes 627 for delivering process gasfrom a gas flow channel 629 to the lower chamber region 602. In someexamples, holes 631 in the gas distribution device 614 align with theholes 627. In other examples, the gas distribution device 614 has asmaller diameter and the holes 631 are not needed. In some examples, theprocess gas is delivered by the one or more spaced holes 627 in adownward direction towards the substrate at an acute angle relative tothe plane including the gas distribution device 614, although otherangles/directions may be used.

In other examples, the upper chamber region 604 is cylindrical with aflat top surface and one or more flat inductive coils may be used. Instill other examples, a single chamber may be used with a spacer locatedbetween a showerhead and the substrate support.

A substrate support 622 is arranged in the lower chamber region 604. Insome examples, the substrate support 622 includes an electrostatic chuck(ESC), although other types of substrate supports can be used. Asubstrate 626 is arranged on an upper surface of the substrate support622 during etching. In some examples, a temperature of the substrate 626may be controlled by a heater plate 617, an optional cooling plate withfluid channels and one or more sensors (not shown); although any othersuitable substrate support temperature control system may be used.

In some examples, the gas distribution device 614 includes a showerhead(for example, a plate 633 having a plurality of spaced holes 635). Theplurality of spaced holes 635 extend from the upper surface of the plate633 to the lower surface of the plate 633. In some examples, the spacedholes 635 have a diameter in a range from 0.1″ to 0.75″. In someexamples, the showerhead is made of a conducting material such asaluminum or a non-conductive material such as ceramic with an embeddedelectrode made of a conducting material.

One or more inductive coils 640 are arranged around an outer portion ofthe dome 618. When energized, the one or more inductive coils 640 createan electromagnetic field inside of the dome 618. In some examples, anupper coil and a lower coil are used. A gas injector 642 injects one ormore gas mixtures from a gas delivery system 650-1.

In some examples, a gas delivery system 650-1 includes one or more gassources 652, one or more valves 654, one or more mass flow controllers(MFCs) 656, and a mixing manifold 658, although other types of gasdelivery systems may be used. A vapor delivery system 659 delivers vaporincluding a carrier gas and another gas to the processing chamber.

A gas splitter (not shown) may be used to vary flow rates of a gasmixture. Another gas delivery system 650-2 may be used to supply an etchgas or an etch gas mixture to the gas flow channels 629 and/or 634 (inaddition to or instead of etch gas from the gas injector 642).

Suitable gas delivery systems are shown and described in commonlyassigned U.S. patent application Ser. No. 14/945,680, entitled “GasDelivery System” and filed on Dec. 4, 2015, which is hereby incorporatedby reference in its entirety. Suitable single or dual gas injectors andother gas injection locations are shown and described in commonlyassigned U.S. Provisional Patent Application Ser. No. 62/275,837,entitled “Substrate Processing System with Multiple Injection Points andDual Injector” and filed on Jan. 7, 2016, which is hereby incorporatedby reference in its entirety.

In some examples, the gas injector 642 includes a center injectionlocation that directs gas in a downward direction and one or more sideinjection locations that inject gas at an angle with respect to thedownward direction. In some examples, the gas delivery system 650-1delivers a first portion of the gas mixture at a first flow rate to thecenter injection location and a second portion of the gas mixture at asecond flow rate to the side injection location(s) of the gas injector642. In other examples, different gas mixtures are delivered by the gasinjector 642. In some examples, the gas delivery system 650-1 deliverstuning gas to the gas flow channels 629 and 634 and/or to otherlocations in the processing chamber as will be described below.

A plasma generator 670 may be used to generate RF power that is outputto the one or more inductive coils 640. Plasma 690 is generated in theupper chamber region 604. In some examples, the plasma generator 670includes an RF source 672 and a matching network 674. The matchingnetwork 674 matches an impedance of the RF source 672 to the impedanceof the one or more inductive coils 640. In some examples, the gasdistribution device 614 is connected to a reference potential such asground. A valve 678 and a pump 680 may be used to control pressureinside of the lower and upper chamber regions 602, 604 and to evacuatereactants.

A controller 676 communicates with the gas delivery systems 650-1 and650-2, the valve 678, the pump 680, and/or the plasma generator 670 tocontrol flow of process gas, purge gas, RF plasma and chamber pressure.In some examples, plasma is sustained inside the dome 618 by the one ormore inductive coils 640. One or more gas mixtures are introduced from atop portion of the chamber using the gas injector 642 (and/or holes 623)and plasma is confined within the dome 618 using the gas distributiondevice 614.

In some examples, an RF bias 684 is provided and includes an RF source686 and an optional matching network 688. The RF bias power can be usedto create plasma between the gas distribution device 614 and thesubstrate support or to create a self-bias on the substrate 626 toattract ions. The controller 676 may be used to control the RF biaspower.

Referring now to FIG. 6B, the vapor delivery system 659 can include abubbler or an ampoule. The vapor delivery system 659 includes a carriergas source 692 that is connected by a valve V1 to a mass flow controller694. The vapor delivery system 659 further includes valves V2, V3, V4,V5 and V6 that are configured to prevent flow or to control flow ofcarrier gas or a mixture of the carrier gas and the solvent. Atemperature sensor 697 and a heater 698 are used to control atemperature of the solvent in an ampoule 696. Carrier gas can besupplied by opening valves P1, V2, V4, V5 and V6. Carrier gas and thesolvent can be supplied by opening valves V1, V2, V3, V5 and V6 andclosing valve V4.

Referring now to FIG. 7, a substrate processing tool 710 according tothe present disclosure is shown. The substrate processing tool 710includes a robot 712 arranged in a central location. The robot 712 maybe operated at vacuum or atmospheric pressure. The substrate processingtool 710 includes a plurality of stations 716-1, 716-2, . . . , and716-S (collectively stations 716) (where S is an integer greater thanone) arranged around the robot 712. The stations 716 may be arrangedaround a center of the substrate processing tool 710 with an equal orirregular angular offset. Examples of stations 716 may includedeposition, etch, pre-clean, post clean, spin clean, etc. The substratesmay be initially located in a cassette 734. A robot and load lockgenerally identified at 738 may be used to move the substrates from thecassette 734 to the substrate processing tool 710. When processing iscomplete, the robot and load lock 738 may return the substrates to thecassette 734 and/or another cassette 739.

In some examples, one of the plurality of stations 716 performsdeposition or etching. Another one of the plurality of stations 716performs cleaning or etching described above. Another one of theplurality of stations such as a spin clean chamber performs the simplewet clean step described above. In some examples, the substrate is movedby the robot 712 from the deposition or etching station, to the cleaningor etching station, and then to the simple wet clean station.

The foregoing description is merely illustrative in nature and is in noway intended to limit the disclosure, its application, or uses. Thebroad teachings of the disclosure can be implemented in a variety offorms. Therefore, while this disclosure includes particular examples,the true scope of the disclosure should not be so limited since othermodifications will become apparent upon a study of the drawings, thespecification, and the following claims. It should be understood thatone or more steps within a method may be executed in different order (orconcurrently) without altering the principles of the present disclosure.Further, although each of the embodiments is described above as havingcertain features, any one or more of those features described withrespect to any embodiment of the disclosure can be implemented in and/orcombined with features of any of the other embodiments, even if thatcombination is not explicitly described. In other words, the describedembodiments are not mutually exclusive, and permutations of one or moreembodiments with one another remain within the scope of this disclosure.

Spatial and functional relationships between elements (for example,between modules, circuit elements, semiconductor layers, etc.) aredescribed using various terms, including “connected,” “engaged,”“coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and“disposed.” Unless explicitly described as being “direct,” when arelationship between first and second elements is described in the abovedisclosure, that relationship can be a direct relationship where noother intervening elements are present between the first and secondelements, but can also be an indirect relationship where one or moreintervening elements are present (either spatially or functionally)between the first and second elements. As used herein, the phrase atleast one of A, B, and C should be construed to mean a logical (A OR BOR C), using a non-exclusive logical OR, and should not be construed tomean “at least one of A, at least one of B, and at least one of C.”

In some implementations, a controller is part of a system, which may bepart of the above-described examples. Such systems can comprisesemiconductor processing equipment, including a processing tool ortools, chamber or chambers, a platform or platforms for processing,and/or specific processing components (a wafer pedestal, a gas flowsystem, etc.). These systems may be integrated with electronics forcontrolling their operation before, during, and after processing of asemiconductor wafer or substrate. The electronics may be referred to asthe “controller,” which may control various components or subparts ofthe system or systems. The controller, depending on the processingrequirements and/or the type of system, may be programmed to control anyof the processes disclosed herein, including the delivery of processinggases, temperature settings (e.g., heating and/or cooling), pressuresettings, vacuum settings, power settings, radio frequency (RF)generator settings, RF matching circuit settings, frequency settings,flow rate settings, fluid delivery settings, positional and operationsettings, wafer transfers into and out of a tool and other transfertools and/or load locks connected to or interfaced with a specificsystem.

Broadly speaking, the controller may be defined as electronics havingvarious integrated circuits, logic, memory, and/or software that receiveinstructions, issue instructions, control operation, enable cleaningoperations, enable endpoint measurements, and the like. The integratedcircuits may include chips in the form of firmware that store programinstructions, digital signal processors (DSPs), chips defined asapplication specific integrated circuits (ASICs), and/or one or moremicroprocessors, or microcontrollers that execute program instructions(e.g., software). Program instructions may be instructions communicatedto the controller in the form of various individual settings (or programfiles), defining operational parameters for carrying out a particularprocess on or for a semiconductor wafer or to a system. The operationalparameters may, in some embodiments, be part of a recipe defined byprocess engineers to accomplish one or more processing steps during thefabrication of one or more layers, materials, metals, oxides, silicon,silicon dioxide, surfaces, circuits, and/or dies of a wafer.

The controller, in some implementations, may be a part of or coupled toa computer that is integrated with the system, coupled to the system,otherwise networked to the system, or a combination thereof. Forexample, the controller may be in the “cloud” or all or a part of a fabhost computer system, which can allow for remote access of the waferprocessing. The computer may enable remote access to the system tomonitor current progress of fabrication operations, examine a history ofpast fabrication operations, examine trends or performance metrics froma plurality of fabrication operations, to change parameters of currentprocessing, to set processing steps to follow a current processing, orto start a new process. In some examples, a remote computer (e.g. aserver) can provide process recipes to a system over a network, whichmay include a local network or the Internet. The remote computer mayinclude a user interface that enables entry or programming of parametersand/or settings, which are then communicated to the system from theremote computer. In some examples, the controller receives instructionsin the form of data, which specify parameters for each of the processingsteps to be performed during one or more operations. It should beunderstood that the parameters may be specific to the type of process tobe performed and the type of tool that the controller is configured tointerface with or control. Thus as described above, the controller maybe distributed, such as by comprising one or more discrete controllersthat are networked together and working towards a common purpose, suchas the processes and controls described herein. An example of adistributed controller for such purposes would be one or more integratedcircuits on a chamber in communication with one or more integratedcircuits located remotely (such as at the platform level or as part of aremote computer) that combine to control a process on the chamber.

Without limitation, example systems may include a plasma etch chamber ormodule, a deposition chamber or module, a spin-rinse chamber or module,a metal plating chamber or module, a clean chamber or module, a beveledge etch chamber or module, a physical vapor deposition (PVD) chamberor module, a chemical vapor deposition (CVD) chamber or module, anatomic layer deposition (ALD) chamber or module, an atomic layer etch(ALE) chamber or module, an ion implantation chamber or module, a trackchamber or module, and any other semiconductor processing systems thatmay be associated or used in the fabrication and/or manufacturing ofsemiconductor wafers.

As noted above, depending on the process step or steps to be performedby the tool, the controller might communicate with one or more of othertool circuits or modules, other tool components, cluster tools, othertool interfaces, adjacent tools, neighboring tools, tools locatedthroughout a factory, a main computer, another controller, or tools usedin material transport that bring containers of wafers to and from toollocations and/or load ports in a semiconductor manufacturing factory.

What is claimed is:
 1. A method for treating a substrate, comprising: a)arranging a substrate in a processing chamber; b) supplying at least oneof a vaporized solvent and a gas mixture to the processing chamber toform a conformal liquid layer on exposed surfaces of the substrate; c)removing the at least one of the vaporized solvent and the gas mixturefrom the processing chamber; and d) supplying a reactive gas including ahalogen species to the processing chamber, wherein the conformal liquidlayer adsorbs the reactive gas to form a reactive liquid layer thatetches the exposed surfaces of the substrate.
 2. The method of claim 1,wherein the reactive liquid layer reacts with the exposed surfaces ofthe substrate to create a gas product.
 3. The method of claim 1, whereinthe exposed surfaces of the substrate are etched without formingresidue.
 4. The method of claim 1, wherein the at least one of avaporized solvent and a gas mixture is selected from a group consistingof a polar solvent, water, peroxide, isopropyl alcohol, acetone, carbontetrachloride, hexane, methanol, and ethanol.
 5. The method of claim 4,wherein the reactive gas is selected from a group consisting of hydrogenfluoride gas, hydrogen chloride gas and hydrogen bromide gas.
 6. Themethod of claim 1, wherein the substrate includes a plurality of highaspect ratio (HAR) features having a depth to width that is greater thanor equal to 5:1.
 7. The method of claim 1, further comprising, prior tosupplying the at least one of the vaporized solvent and the gas mixtureto the processing chamber, setting a pressure in the processing chamberto a pressure range from 1 Torr to 10 Torr.
 8. The method of claim 1,further comprising, prior to supplying the at least one of the vaporizedsolvent and the gas mixture to the processing chamber, settingprocessing temperature in the processing chamber to a temperature rangefrom 0C° to 400° C.
 9. The method of claim 1, wherein the reactiveliquid layer etches the exposed surfaces at an etch rate in a range from10 Angstroms/min to 100 Angstroms/min.
 10. The method of claim 1,further comprising performing a plurality of cycles including a) to d).11. The method of claim 10, wherein the reactive liquid layer etches theexposed surface 0.2 Angstroms to 1 Angstrom during each cycle of theplurality of cycles.
 12. The method of claim 1, further comprising:prior to b): supplying an oxidizing gas to the processing chamber for apredetermined period; and evacuating the oxidizing gas.
 13. The methodof claim 12, wherein the oxidizing gas includes a gas selected from agroup consisting of molecular oxygen, ozone, hydrogen peroxide, nitrousoxide and nitrogen dioxide.
 14. The method of claim 12, wherein theoxidizing gases are supplied with remote plasma.
 15. The method of claim12, wherein the oxidizing gases are supplied at a processing temperaturein a range from 100° C. to 400° C.
 16. The method of claim 12, furthercomprising performing wet cleaning of the substrate after d).
 17. Themethod of claim 12, wherein the reactive liquid layer reacts with theexposed surfaces of the substrate to create a gas product.
 18. Themethod of claim 1, wherein the exposed surfaces of the substrate areetched without forming residue.
 19. The method of claim 1, wherein a) tod) are performed in an inductively coupled plasma (ICP) chamber.